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  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<script>
  //ForEach 迭代(遍历) 数组
  var arr = [1,2,3];
  var sum = 0;
  arr.forEach(function(value,index,array){
      console.log('每一个数组元素'+ value);
      console.log('每一个数组元素的索引号' + index);
      console.log('数组本身' + array);
      sum += value;
      
  })
  console.log(sum);
</script>
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